1. Technical Field
This invention relates to electrostatographic apparatus for producing fused toner images on receiver sheets, and more particularly, to such an apparatus which includes a heated fusing device, as well as sheet cooling and turnover devices.
2. Background Art
Electrostatographic apparatus such as copiers and printers are well known for producing fused toner images on receiver sheets. In such apparatus, the toner images are first formed on an image-bearing member and then transferred to one or a first, side of the receiver sheet. Subsequently, the receiver sheet is fed through a fusing device, that typically includes a heat source, where the toner images on the sheet, and the sheet itself, are heated in order to melt and thus fuse the toner images onto the sheet. The sheet may then be moved to a finishing area for immediate handling, or for accumulation, stapling, and handling thereafter. In order to prevent such sheets from sticking to each other, and in order to insure high quality for the fused images, the melted or fused toner must be quickly cooled before such accumulation and handling.
In some such apparatus, such post fusing handling includes reversing or turning over the receiver sheet so that a toner image, similarly formed, can be transferred to the other, or second, side of the sheet. Turning over the sheet, as such, takes time, and so also does cooling the same sheet as above.
Unfortunately, however, as electrostatographic apparatus are made to operate at higher and higher speeds, this usually requires higher and higher temperatures at the heat source of the fusing device in order to effectively fuse the toner image in a shortened cycle time, as well as shorter and shorter times for such post fusing cooling and turnover functions of the apparatus. Furthermore, customer demans for such apparatus to become smaller and more compact, as well as less expensive, are combining with the trend towards higher and higher speeds to create problems for conventional electrostatographic apparatus with separate, bulky and expensive devices for cooling and turning over receiver sheets.